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Dynaco ST-70 Restoration Module 

Assembly, Installation, and Adjustment Manual

 

Page 1 

CAE Dynaco Driver Restoration Module PC-3R – R0: 7-02 

 

 
I. Introduction 
 

Thanks for your purchase of our ST-70 Driver Restoration PC Board. It has been 
designed to provide an exact replacement for the original Dynaco input driver card (Dyna 
PC-3) using dramatically improved construction materials (Mil Spec FR-4 fiberglass). It 
has been designed to drop into the original PC-3 position without any electrical or 
mechanical changes to your ST-70. Once installed, the reliability of your ST-70 will be 
greatly improved and its stability significantly enhanced.  
 
This document describes the specific instructions and steps associated with our Dynaco 
Upgrade board (PC-3R). Additional documents referenced (and available from our web 
page) are:  
 

a. 

 

General Overview Assembly Notes (CAE Tech Note # 1) 

b. 

 

Soldering Tutorial (CAE Tech Note # 2) 

c. 

 

Recommended Tools & Test Instruments (CAE Tech Note # 3) 

 
Please take the time to familiarize yourself with all of these documents in particular Tech 
Note # 1. 
 

 
II. General Overview 
 

Take time to review all of the documentation provided including the aforementioned tech 
notes related to soldering technique and proper tools and test equipment. In the following 
sections we will guide you through several project phases. Each section has been 
carefully prepared with our own notes and comments from our customers to be sure that 
any anticipated question has been considered. The sequence is identical to that which we 
follow when we complete the fabrication for our customers. Please follow the same 
sequence to maximize efficiency and eliminate errors. It is also very helpful to read each 
section before beginning to gain a visual idea of the construction.  
 
Your project will be built in stages. If you have purchased the PC Board in its 
unassembled form (PWB-PC3U) you will first assemble the components onto that board. 
Next, you will remove the original Dynaco PC-3 board and carefully label each of the 
associated wires. You will then install the CAE replacement upgrade PC Board and 
reconnect the original wires to their corresponding terminals followed by a few electrical 
tests and power up sequence.  
 
Finally you will check and set the bias of the output stage.  
 

Summary of Contents for Dynaco ST-70 Restoration Module

Page 1: ...particular Tech Note 1 II General Overview Take time to review all of the documentation provided including the aforementioned tech notes related to soldering technique and proper tools and test equip...

Page 2: ...re associated with soldering related errors b Diodes transistors IC s all semiconductors and many capacitors always electrolytic types are polar this means that there is a right and wrong way to inser...

Page 3: ...to Figure 1 Top View PC Board Component Placement Diagram The board has been designed so that a gentle radius near the body of the resistor will position the leads in alignment with the associated hol...

Page 4: ...ext begin desoldering each wire from the original PC 3 card The original Dynaco wires were solid PVC insulated The PVC is not very tolerant of heat and therefore you should be very careful not to melt...

Page 5: ...oard should be mounted so that the top surface of the PC Board rests inside the Dynaco ST 70 chassis cutout as per the original Be careful not to capture any wires and secure the board in places with...

Page 6: ...ier tube and the two left channel output tubes Do not install the right channel output tubes right now Replace the original 3A fuse Rotate both original Bias Potentiometers fully counterclockwise Conn...

Page 7: ...Dynaco ST 70 Restoration Module Assembly Installation and Adjustment Manual Page 7 CAE Dynaco Driver Restoration Module PC 3R R0 7 02 Figure 1...

Page 8: ...R9 R10 RESISTOR CARBON FILM 4 MSR 29SJ500 270K 270K 1 2W R11 R12 RESISTOR CARBON FILM 2 MSR 29SJ500 10 10 1 2 W R13 R14 RESISTOR METAL FILM 2 MSR 29MF500 47 5 47 5 1 2 W R15 R16 RESISTOR METAL OXIDE 2...

Page 9: ...Dynaco ST 70 Restoration Module Assembly Installation and Adjustment Manual Page 9 CAE Dynaco Driver Restoration Module PC 3R R0 7 02...

Page 10: ...Dynaco ST 70 Restoration Module Assembly Installation and Adjustment Manual Page 10 CAE Dynaco Driver Restoration Module PC 3R R0 7 02...

Page 11: ...Dynaco ST 70 Restoration Module Assembly Installation and Adjustment Manual Page 11 CAE Dynaco Driver Restoration Module PC 3R R0 7 02...

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